Positive resist composition and pattern forming method

Abstract

A positive photosensitive composition comprises (A) a resin that has an acid decomposable repeating unit represented by formula (I) and increases its solubility in an alkali developer by action of an acid; (B) a compound generating an acid in irradiation with actinic light or radiation; (C) a resin that contains neither fluorine nor silicon and has a repeating unit having the predetermined structure; and (D) a solvent, wherein each symbol represents a predetermined group.

1. A positive photosensitive composition comprising:
 (A) a resin that has an acid decomposable repeating unit represented by formula (I) and increases its solubility in an alkali developer by action of an acid; 
 (B) a compound generating an acid in irradiation with actinic light or radiation; 
 (C) a resin that contains neither fluorine nor silicon and has at least one repeating unit selected from repeating units represented by formulas (C-I) to (C-III); and 
 (D) a solvent, 
 
       
         
           
           
               
               
           
         
         wherein, in the formula (I), 
         Xa 1  represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, 
         Ry 1  to Ry 3  each independently represents an alkyl group or a cycloalkyl group, and at least two of Ry 1  to Ry 3  may be coupled to form a ring structure, and 
         Z represents a divalent linking group, 
       
       
         
           
           
               
               
           
         
         wherein, in the formulas (C-I) to (C-III), 
         R 1 s each independently represents a hydrogen atom or a methyl group, 
         R 2 s each independently represents a hydrocarbon group having at least one —CH 3  partial structure, 
         P 1  represents a single bond or a linking group having an alkylene group, an ether group or two or more thereof, 
         P 2  represents a linking group selected from —O—, —NR— (in which R represents a hydrogen atom or an alkyl group) and —NHSO 2 —, and 
         n stands for an integer from 1 to 4; and 
         wherein the amount of the resin (C) is from 0.1 to 5 mass % based on total solids content of the composition. 
       
     
     
       2. A positive resist composition according to  claim 1 ,
 wherein Z in the formula (I) is a divalent linear hydrocarbon group or a divalent cyclic hydrocarbon group. 
 
     
     
       3. A positive resist composition according to  claim 1 ,
 wherein the resin (A) further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group and an acid group. 
 
     
     
       4. A positive resist composition according to  claim 1 ,
 wherein the compound (B) comprises a compound generating an acid represented by formula (BII): 
 
       
         
           
           
               
               
           
         
         wherein, in the formula (BII), 
         Rb 1  represents a group having an electron withdrawing group, 
         Rb 2  represents an organic group having no electron withdrawing group, 
         m and n each stands for an integer from 0 to 5 with the proviso that m+n≦5, 
         when m stands for 2 or greater, a plurality of Rb 1 s may be the same or different, and 
         when n stands for 2 or greater, a plurality of Rb 2 s may be the same or different. 
       
     
     
       5. A positive resist composition according to  claim 4 ,
 wherein in the formula (BII), m stands for from 1 to 5 and the electron withdrawing group of Rb 1  is at least one atom or group selected from a fluorine atom, a fluoroalkyl group, a nitro group, an ester group, and a cyano group. 
 
     
     
       6. A positive resist composition according to  claim 1 ,
 wherein the resin (C) further has a repeating unit represented by formula (C): 
 
       
         
           
           
               
               
           
         
         wherein, in the formula (C), 
         X 1 , X 2  and X 3  each independently represents a hydrogen atom, an alkyl group, or a halogen atom, 
         L represents a single bond or a divalent linking group, and 
         Rp 1  represents an acid decomposable group. 
       
     
     
       7. A positive resist composition according to  claim 6 ,
 wherein the repeating unit represented by the formula (C) is a repeating unit represented by formula (C1). 
 
       
         
           
           
               
               
           
         
         wherein, in the formula (C1), 
         X 1 , X 2  and X 3  each independently represents a hydrogen atom, an alkyl group, or a halogen atom, and 
         R 12 , R 13  and R 14  each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group with the proviso that at least one of R 12 , R 13  and R 14  represents an alkyl group, or two of R 12 , R 13  and R 14  may be coupled to form a ring. 
       
     
     
       8. A positive resist composition according to  claim 1 , for use in exposure to light having a wavelength of 200 nm or less. 
     
     
       9. A pattern forming method comprising:
 forming a resist film with a positive resist composition as claimed in  claim 1 ; and 
 exposing and developing the resist film. 
 
     
     
       10. A pattern forming method according to  claim 9 ,
 wherein the resist film is exposed via an immersion liquid.